The city state of Ayutthaya in time, grew to become an important trade player in south-east Asia. Trade was vigilantly controlled by the Ayutthayan Court. Customs houses were established in the cardinal directions around the city along the important waterways with a double function: control of persons and goods, and most important for the court, collect taxes. There were four main customs posts called the "Royal Customs Posts of the Four Directions".

The northern tax station was situated near Ban Bang Luang in the turn of Ban Maen and on the Pho Sam Ton waterway, in fact the old Lopburi River. It stood behind Wat Na Phra That. The latter temple could not be traced back by the author. Wat Na Phra That would have been a reliquary temple as its name suggests, but this kind of temple was always built within the city walls. There are as thus strong doubts about its denomination. A contender could be Wat Tha Yak, which was situated on the northern junction point of the old Lopburi River and a khlong lat (short cut) called Khlong Bang Khuat. The latter canal had been dug through the oxbow of the old Lopburi River, to straighten the waterway. Wat Tha Yak is seated on the Pho Sam Ton waterway, at a stone's throw from present Ban Maen (Maen Village) and just south of Wat Dao Khanong. [1]

The eastern tax station was situated in the area of Ban Khao Mao. This station must probably have been situated on the junction of present Khlong Hantra and Khlong Khao Mao in the immediate vicinity of Wat Krasang. [1]

The southern tax station was the most important and largest customs house as it controlled all the incoming and the outgoing sea vessels. It was located near Wat Protsat at Bang Tanaosi in present Khanon Luang sub-district of Bang Pa-In, south of Ko Rian. [1] The custom station was called by the French the "Tabanque" and is indicated on Bellin's map as thus. (1)

Finally, the western tax station was situated on the Maha Phram Canal at Ban Pak Khu (Ban Mai sub-district). It controlled the navigation coming from and going to the Chao Phraya River (at present the Noi River), which at that time ran a few kilometers west of the city. The tax station was situated south of Wat Lat Bua Khao and north of Wat Khanon. [1]

Each toll house had two officers and twenty serfs (2) who worked in shifts of 15 days and were then rotated. At the customs house there were horses and fast boats to send urgent dispatches to the capital in case of incidents. Boats were checked for prohibited items and weapons as prescribed by law. Guard boats were making inspections up and down the river, while at night rafts with torches were anchored mid-stream to allow guards to inspect the night traffic. [3] At the toll houses, import and export duties were collected from ships going to and leaving the capital.

Along the route from the mouth of the Chao Phraya River until Ayutthaya there were guard-vessels and strict vigilance. The ship captains needed to disembark and register their names and all their goods and armament at a checkpoint manned by a mandarin at the mouth of the river. After the registration a passport was obtained to proceed to Ayutthaya. Denton, one of the English factors, recorded that "when going first to the capital, they learned that the crews of two Japanese junks, then in the river, had traded by force, having entered the city walls without a license. The result was that eight of their number were killed in one day, whereas if they had first procured the necessary Tarra or license, all would have been well." [4]

For all ships trading with foreign countries the government levied taxes according to the width of the ship, every time the ship entered and left a port of Siam. The duty collected by the government was according to the width at the gunnels (3) and calculated per Wa (4). The duty was levied on all ships whether they belonged to the Siamese, the Chinese, the Chams, the Indians, or the Europeans; but the rate could differ depending the nationality of the vessel. Favoured nations paid a tax of 12 Baht per Wa, while the rest was taxed at 20 Baht per Wa. [5] Import duty was also levied on the merchandise of incoming vessels. On ships from friendly countries such as China, tax was collected at a rate of 2 in 12; other foreign merchants paid at a rate of 2 in 9. It was estimated that the state collected 800 gold pieces a year at these customs checkpoints and 3,000 gold pieces a year from galleon taxes towards the end of the Ayutthaya period. Anyone importing goods into the Kingdom would also expect the customs officials to take a rake-off of part of the merchandise.

Some of the custom houses are mentioned in the Royal Chronicles of Ayutthaya. After the rainy season in 1563, Burma started a campaign against Ayutthaya (the White Elephant War). The King of Hongsawadi, Bayin Naung, arrived in March 1564 and erected his royal stockade at Kum Dong. The battle lingered on and King Chakkraphat (r. 1548-1569) had the Narai Sanghan Cannon taken on board a junk and hauled up by way of Pom Village. A ground force to protect both banks was prepared and ascended to the Pak Khu Customs House. The canon was fired and the cannonball fell inside the stockade near the pavilion of the King of Hongsawadi. The later ordered the site abandoned and went to establish his royal stockade on the Phutthalao Plain. [6]

In 1568, the Burmese set out again against Ayutthaya, arriving in January 1569 in the vicinity of the capital. The Burmese construct a number of military stockades in a circle around the city. The main army set up its stockade at Wat Pho Phuak Township, on the Pak Khu tax station rice-fields. Finally Ayutthaya fell to the Burmese. [7]

In 1586, the King of Hongsawadi invested Siam again. He arrived at Ayutthaya on Thursday, the second day of the waxing moon of the month of January and entrenched his army in the vicinity of the Pak Khu customs house. Nanthasu was sent to take up positions in the vicinity of the Lang Village customs house on the eastern bank of the river with an army of five thousand men and four hundred kacang laokha boats. [8]

After having set up an army camp in the vicinity of Wat Chong Lom, Prince Naresuan and his brother Prince Ekathotsarot loaded the Phra Maha Maruttayurat gun onto a junk on the eighth day of the waxing moon of the month of July 1586 and taken up to fire on the King of Hongsawadi’s stockade at the Pak Khu customs house. The King of Hongsawadi, seeing that the Siamese were able to reach the stockade with their fire, withdrew his army and encamped at Pa Mok Yai. [9]

The customs house figures also in the Siamese epic story Khun Chang Khun Phaen: "People catching sight of them broke into laughter. ‘Those bald elephants go very well together!’ They shouted at others to come and look. Khun Chang hid his face and looked away. They passed the Don Fak customs post beside Pak Khu. Lots of people come to look at the throng of elephants and horses. They made for the plain towards Talan". [10]

(The "Tabanque ou Douane"on a French map)

Footnotes:

(1) Simon de La Loubère wrote regarding the customs house at the mouth of the Chao Phraya River: "The King’s Ambassadors arrived thus within two Leagues of Siam, at a place which the French called the Tabanque; and they waited there eight or ten days for the time of their entrance into the Metropolis. Tabanque in Siamese signifies the Custom House: and because the Officer’s House, which stands at the Mouth of the River, is of Bambou like all the rest, the French gave the name of Tabanque to all the Bambou houses where they lodged, from the name of the Officers House, which they had seen first of all." [11](2) Serfs or Phrai were neither slave nor free, but commoners which served a master periodically with unpaid labour. [2](3) Gunnel or gunwale is a nautical term - the top of the side of a boat or the topmost plank of a wooden vessel. It was called as thus because guns were mounted on it.(4) Traditional Thai unit of length equal to 2 meters.